Question

Discuss in detail the role that oxygen play in acclimation to various stresses. FOR 20 MARKS

Answer 1

Oxygen play very important role in acclimation to various stresses as reactive oxygen species ROS especially to abiotic stress. It act as a signal transduction molecules in different pathways invovled in plant acclimation resposne to stress, but are also degrade the toxic byproducts of stress metabolism. Metabolic and signaling ROS are the two major sources of ROS during abiotic stress which influence the mechanism involved in plant acclimation to stress through redox reactions which control transcription and translation of stress acclimation proteins and enzymes. It also directly affect the redox state of regulatory proteins which alter the process of transcription and translation that could activate the acclimation response that would mitigate the effects of stress on metabolism and also lowers the level of metabolically produced ROS. ROS can be produced at various subcellular compartments like chloroplast and apoplast. Specificity int hese subcellualr ROS arises seperately for each set of environmental conditions like drought, salinity, cold, heat, etc., Hydrogen peroxide can be transported across membranes in a regulated process via aquoaporins. Different proteins and hormones mediates the interactions of ROS which activates acclimation responses by ROS. Along with altering proteins and altering metabolic fluxes and transcription, it also result in affeting various lant hormones, such as abscisic acid (ABA), auxin, brassinosteroids (BRs), gibberellins (GAs) and NO.